Be careful while driving

The sudden appearance of purple street lights may not seem harmful, but they may affect the safety of drivers and pedestrians.

Upgrading the wick of street lights to light-emitting diodes (LEDs) is indeed a wise move. According to data from the US Department of Energy, LED is currently one of the most energy-efficient lighting technologies. In addition, LED lights are more durable, 

have a longer lifespan, and produce superior lighting quality compared to other lighting methods.

These diodes can emit light of multiple wavelengths, but cannot naturally produce white light. Therefore, white LED lights on the streets actually emit a mixture of red, green, and blue (or red, yellow, and blue) colors simultaneously. There are two common 

methods to make an LED light look like a light source emitting white light: the first is to combine miniature LED lights that emit red, green, or blue light into a large device. Another method is to use only blue LED lights, but apply a fluorescent substance - a 

phosphor - inside the lamp tube. When the blue light emitted by the diode passes through the phosphor coating, the phosphor absorbs a portion of the blue light and emits red and yellow light, which also produces a mixed white light.